CVE-2025-61865 is a security vulnerability affecting multiple NAS management applications developed by I-O DATA DEVICE, INC., specifically the NarSuS App versions prior to 2.33. The root cause is the registration of Windows services with unquoted file paths. In Windows, unquoted service paths containing spaces can be exploited by placing malicious executables in specific locations along the path, which the system may execute with elevated privileges. Here, if a user has write permissions on the root directory of the system drive (commonly C:\), they can place a crafted executable that will be run with SYSTEM privileges when the service starts or restarts. This effectively allows privilege escalation from a user with limited local access to full SYSTEM-level control, compromising confidentiality, integrity, and availability of the affected system. The CVSS v3.0 score of 6.7 reflects a medium severity, considering the attack vector is local (AV:L), requires low complexity (AC:L), but demands high privileges (PR:H) and no user interaction (UI:N). The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). No public exploits have been reported yet, but the vulnerability poses a significant risk in environments where users have write access to the system drive root. The vulnerability is particularly relevant for organizations using I-O DATA's NAS devices managed via the NarSuS App, which are common in small to medium enterprises and some critical infrastructure sectors.

For European organizations, this vulnerability presents a notable risk especially in environments where endpoint security policies are lax, allowing users write access to system drive roots. Successful exploitation leads to full SYSTEM privilege escalation, enabling attackers to install persistent malware, exfiltrate sensitive data, disrupt NAS services, or pivot within the network. This can severely impact data confidentiality, system integrity, and availability of critical storage infrastructure. Sectors such as finance, healthcare, manufacturing, and government agencies that rely on NAS devices for data storage and backup are particularly vulnerable. The medium CVSS score indicates a moderate but actionable threat, with potential for significant operational disruption if exploited. The absence of known exploits reduces immediate risk but should not lead to complacency. European organizations with distributed NAS deployments or remote/local user access should be vigilant. The threat also underscores the importance of strict permission management and service path hygiene in Windows environments.

1. Immediately upgrade the NarSuS App to version 2.33 or later where the unquoted service path issue is resolved. 2. Audit and restrict write permissions on the root directory of the system drive (e.g., C:\) to prevent unauthorized file placement. 3. Regularly review Windows service configurations to ensure all service paths are properly quoted and do not contain spaces that could be exploited. 4. Implement application whitelisting and endpoint protection solutions to detect and block unauthorized executable files in critical system locations. 5. Monitor system logs and service start events for anomalies that may indicate exploitation attempts. 6. Educate local users about the risks of placing files in system directories and enforce least privilege principles. 7. For environments where patching is delayed, consider temporary mitigations such as disabling vulnerable services if feasible or isolating affected devices from critical networks. 8. Conduct penetration testing and vulnerability assessments focused on local privilege escalation vectors to identify similar risks.